Productivity improvement has been required in component mounting apparatuses these days. Particularly, production interruption subsequent to switching of product types (kinds) and lack of components adversely influences productivity, and therefore improvement in this field is strongly demanded.
Prior art known for enhancing operation of a component feed part of a component mounting apparatus is disclosed, e.g., in Japanese Unexamined Patent Publication No. 60-206098.
This prior art apparatus will be described below with reference to FIGS. 10 and 11.
A constitution of an entire component mounting apparatus will be schematically depicted first. FIG. 10 shows a component mounting apparatus of a high-speed type, and FIG. 11 shows a component mounting apparatus of a multi-functional middle-speed type.
In FIG. 10, a component mounting apparatus 10 of a high-speed type comprises an operation part 11, a control part 12, mounting heads 13, a mounting table 14, a transfer rail 15, and a component feed part 16. The component feed part 16 loads a plurality of parts cassettes 16a which slide to feed predetermined components to the mounting heads 13. The mounting table 14 holds printed boards 1, and positions the boards sequentially to mount the predetermined components.
In FIG. 11, a component mounting apparatus 110 of a multi-functional middle-speed type comprises an operation part 111, a control part 112, a mounting head 113, a board recognition device 113a, a component inspection part 113b, a mounting table 114, a transfer rail 115, and a component feed part 116. The component feed part 116 is equipped with a parts cassette 116a, a bulk cassette 116b, a parts tray container part 116c, and parts trays 116d, so that many kinds of components 5 can be supplied from the component feed part 116. The mounting head 113 removes an electronic component 5 from the component feed part 116, moves the component to a predetermined component mounting position of the mounting table 114, and then mounts the component onto a printed board 1.
The following description will be directed to how a component feed part is conventionally switched to cope with a lack of components in a component mounting apparatus.
FIG. 8A is an explanatory diagram of an example of a conventional exchange mode, FIG. 8B is an explanatory diagram of an example of a conventional preparation mode, and FIGS. 9A and 9B are schematic diagrams of examples of a conventional switch mode in an alternate operation and a mounting program, respectively.
According to the conventional exchange mode shown in FIG. 8A, component feed part 16, 116 is divided into two groups A and B, and the same parts are arranged at the same positions in groups A and B, respectively, so that, for instance, group A if lacking in components is switched for group B.
In the conventional preparation mode shown in FIG. 8B, the component feed part 16, 116 is divided into two groups A and B and, components to be mounted to A-type boards and B-type boards are arranged in groups A and B, respectively, thereby coping with switching of types of boards to be produced.
As is disclosed in publication No. 60-206098 referred to earlier, according to the conventional alternate operation shown in FIGS. 9A and 9B, spare components are removed from cassettes of a preliminarily designated spare component feed part when a component feed part lacks components (in other words, the component feed part is switched for the spare component feed part), so that production is continued. More specifically, when a parts cassette P1 by way of example is depleted of components in the component feed part 16, 116, the component feed part is switched to a feed position Z1=Zn, Zn=Zn+1 designated by spare component information 20c, thereby automatically switching to spare components to continue production.
In the above-described prior art constitution, it is necessary to construct the component feed part for spare components into units for each kind of board to be produced, or set spare components at the component feed part in the same arrangement for each kind of board to be produced; that is, it is necessary to assign component information (referred to as spare component information hereinafter) indicating respective set positions of spare components at the component feed part within a mounting program (relating to NC program or component arrangement or the like) designed for mounting components to printed boards of optional kinds.
Components should be set at a designated component feed position at the component feed part. A mounting program indicating the spare component information should be formed for each kind of board in the case of production of a wide variety of boards with a relatively low volume. Moreover, the mounting program should be replaced, or a similar preparation process is needed for switching kinds of boards to be produced. In other words, switching is complicated and takes time, thereby increasing an operator's burden for preparation, management, and the like of the switching.
If spare components are set at a wrong position at a time of switching production, and when the component feed part is depleted of components, components designated as spare components at a component feed position, although this position is wrong, are automatically continuously mounted during an exchange mode or alternate operation, resulting in a quality issue.
During execution of the exchange mode or alternate operation, operation is wasted if components are mounted in a mounting order before being changed, thereby greatly worsening production time per one board, i.e., mounting cycle time, and thus productivity is deteriorated.